This invention relates to a textile yarn carrier or tube especially adapted to the press or compression dyeing of yarn so as to avoid skips or inadequate dyeing of the yarn next to the vertical ribs of prior art yarn carriers.
Yarn carriers in accordance with the invention are preferably made of thermoplastic material and are generally cylindrical. However, they taper or are reduced sufficiently on at least one end to allow an end of one yarn carrier to be inserted into a base end of the next adjacent yarn carrier to the extent necessary to permit a predetermined amount of compression of the yarn on the carriers. A wavy or undulating peripheral surface is provided so that the waves run in an axial direction guiding the tubes for insertion into one another. The head or top end of one tube can be inserted so that its outside diameter extends into the open foot or base end of the next adjacent tube in the inside diameter. The thermal and/or wet treatment of the yarn, as during compression dyeing, is usually carried out with yarn packages which are wound crossed or parallel to allow easy further processing with low thread tension and minimal waste.
Such yarn carrier must possess great strength to withstand substantial compressive forces resulting from shrinkage of the yarn package during thermal treatment or a change in volume during wet treatment and the configuration of yarn carriers constructed in accordance with the invention provides such strength together with economy while facilitating complete and uniform dyeing of the yarn avoiding skips. Upon liquid application rayon and acrylic yarns, for example, have a tendency to expand and, therefore, increase compressive forces whereas polyester tends to shrink increasing radial constricting forces.
Prior textile yarn tubes are usually provided with bar-shaped supporting elements or ribs disposed in an axial direction, so as to resist axial compression which is imparted during compression dyeing. For compression dyeing the yarn packages are stacked upon a vertical pipe or spindle having spaced openings for introducing liquid dye. The yarn carriers are firt nested and then the yarn is compressed as permitted by the respective yarn carriers to the extent one carrier may be inserted into the next adjacent yarn carrier.
The prior art textile yarn tubes, during such dyeing, impart blank spots or skips, that is to say places which are not dyed, to the first yarn layers which rest adjacent the axial ribs. Skips are produced because it is impossible for the dye liquor to penetrate completely through these initial thread layers. These dyeing defects arise especially in synthetic yarn packages, since synthetic yarns are dyed only by means of a liquor under pressure passing from inside outwards. Such ribbed constructions are exemplified in U.S. Letters Pat. Nos. 4,078,740 and 4,180,219. A tapered yarn carrier having an undulating surface over an intermediate part of its length is illustrated in French Patent No. 1,017,666 of 1952.